Among the 34 U.S. states in February 1861, seven Southernslave states individually declared their secession from the U.S. to form the Confederate States of America, or the South. The Confederacy grew to include eleven slave states. The Confederacy was never diplomatically recognized by the United States government, nor was it recognized by any foreign country (although the United Kingdom and France granted it belligerent status). The states that remained loyal to the U.S. (including the border states where slavery was legal) were known as the Union or the North.

The Union and Confederacy quickly raised volunteer and conscription armies that fought mostly in the South over the course of four years. The Union finally won the war when General Robert E. Lee surrendered to General Ulysses S. Grant at the Battle of Appomattox Court House, followed by a series of surrenders by Confederate generals throughout the southern states. Four years of intense combat left 620,000 to 750,000 people dead, more than the number of U.S. military deaths in all other wars combined (at least until approximately the Vietnam War).[15] Much of the South's infrastructure was destroyed, especially the transportation systems. The Confederacy collapsed, slavery was abolished, and 4 million slaves were freed. The Reconstruction Era (1863–1877) overlapped and followed the war, with the process of restoring national unity, strengthening the national government, and granting civil rights to freed slaves throughout the country. The Civil War is the most studied and written about episode in U.S. history.[16]

Overview

In the 1860 presidential election, Republicans, led by Abraham Lincoln, supported banning slavery in all the U.S. territories. The Southern states viewed this as a violation of their constitutional rights and as the first step in a grander Republican plan to eventually abolish slavery. The three pro-Union candidates together received an overwhelming 82% majority of the votes cast nationally: Republican Lincoln's votes centered in the north, DemocratStephen A. Douglas' votes were distributed nationally and Constitutional UnionistJohn Bell's votes centered in Tennessee, Kentucky, and Virginia. The Republican Party, dominant in the North, secured a plurality of the popular votes and a majority of the electoral votes nationally, thus Lincoln was constitutionally elected president. He was the first Republican Party candidate to win the presidency. However, before his inauguration, seven slave states with cotton-based economies declared secession and formed the Confederacy. The first six to declare secession had the highest proportions of slaves in their populations, a total of 49 percent.[17] Of those states whose legislatures resolved for secession, the first seven voted with split majorities for unionist candidates Douglas and Bell (Georgia with 51% and Louisiana with 55%), or with sizable minorities for those unionists (Alabama with 46%, Mississippi with 40%, Florida with 38%, Texas with 25%, and South Carolina, which cast Electoral College votes without a popular vote for president.[18] Of these, only Texas held a referendum on secession.

Eight remaining slave states continued to reject calls for secession. Outgoing Democratic President James Buchanan and the incoming Republicans rejected secession as illegal. Lincoln's March 4, 1861, inaugural address declared that his administration would not initiate a civil war. Speaking directly to the "Southern States", he attempted to calm their fears of any threats to slavery, reaffirming, "I have no purpose, directly or indirectly to interfere with the institution of slavery in the United States where it exists. I believe I have no lawful right to do so, and I have no inclination to do so."[19] After Confederate forces seized numerous federal forts within territory claimed by the Confederacy, efforts at compromise failed and both sides prepared for war. The Confederates assumed that European countries were so dependent on "King Cotton" that they would intervene, but none did, and none recognized the new Confederate States of America.

The American Civil War was one of the earliest true industrial wars. Railroads, the telegraph, steamships and iron-clad ships, and mass-produced weapons were employed extensively. The mobilization of civilian factories, mines, shipyards, banks, transportation and food supplies all foreshadowed the impact of industrialization in World War I, World War II and subsequent conflicts. It remains the deadliest war in American history. From 1861 to 1865, it is estimated that 620,000 to 750,000 soldiers died,[21] along with an undetermined number of civilians.[c] By one estimate, the war claimed the lives of 10 percent of all Northern males 20–45 years old, and 30 percent of all Southern white males aged 18–40.[23]